Physicists have recognized light to be a pure form of energy that is a part of the electromagnetic radiation spectrum. Within this spectrum, the various colors of light each represent unique wavelengths and frequencies that produce therapeutic effects when absorbed through the skin of the body. Near infrared wavelengths are longer than visible light wavelengths, and have been found to penetrate to a deeper level of muscle, bones and joints. Visible red light tends to stimulate growth at the cellular level whereas blue light has more of a soothing affect.
Further scientific research has found that the application of low-level light therapy on the body produces a photochemical reaction in the cell. During this process, a photon of light is absorbed into the treated cell to increase and stimulate stored energy. As a result, this stored energy can be used to perform various cellular tasks and produce increased levels of ATP, NADH, protein, RNA, and nitric oxide.
The effect of light on nitric oxide and the cardiovascular system is well known. Red blood cells and endothelial cells absorb light wavelengths directly through the skin, which release nitric oxide into the smooth muscle cells lining small blood vessels. In the cell, the nitric oxide binds to the enzyme, guanylate cyclase, and increases levels of cyclic guanosine monophosphate, causing the smooth muscle cell to relax. This leads to vasodilation.
This vasodilation effect can result from both natural and artificial light. Studies have shown that red and near infrared light enhance the release of nitric oxide, and thus vasodilation. Infrared wavelengths are longer than visible light wavelengths, and have been found to penetrate to a deeper level of muscle, bones and joints.
Low level light therapy enhances blood flow, as documented in the following reports, which are incorporated herein by specific reference for all purposes (the abstracts are attached as an appendix to U.S. Provisional Application No. 61/809,937, to which this application claims priority):    Zaidi, et al., “Transient Repetitive Exposure to Low Level Light Therapy Enhances Collateral Blood Vessel Growth in the Ischemic Hindlimb of the Tight Skin Mouse,” Photochem. Photobiol., Dec. 11, 2012.    Okuni, I., “Phototherapy in Rehabilitation Medicine,” Masui., July 2012.    Saied, et al., “The diabetic foot and leg: combined He—Ne and infrared low-intensity lasers improve skin blood perfusion and prevent potential complications. A prospective study on 30 Egyptian patients,” Lasers Med. Sci., September 2011.    Plass, et al., “Light-induced vasodilation of coronary arteries and its possible clinical implication,” Ann. Thorac. Surg., April 2012.    Shurygina, et al., “Effect of infrared low-intensity laser therapy on orbital blood circulation in children with progressive short sightedness,” Vopr Kurortol Fizioter Lech Fiz Kult., September-October 2009.